Telescopic hoist.



No. 7.|5,7|5. y l f Patented nec. 9, |902.

F. c. WEBER. 1 TELESCUPIC HOIST.

, Applicatfn filed July 31, 1902.)'

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UNITED `STATES PATENT OFFICE.

FREDERICK C. WEBER, OF PITTSBURG, PENNSYLVANIA.

TELESCOPIC HOIST.

SPECIFICATION forming part of Letters Patent No. 715,715, dated. December 9, 1902.

Application led July 31,1902.

To a/ZZ whom, it may concern:

Be it known that I, FREDERICK C. WEBER, a citizen of the United States, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Telescopic Hoists, of which the following is a specification, reference .being had therein to the accompanying drawings.

This invention pertains to air-hoists, and has particular reference to a double or telescopic hoist of improved construction which may be used interchangeably either as a single or double hoist without increase of head room over that required for the ordinarysingle hoist.

In its present adaptation the invention finds embodiment in two telescoping cylinders, one Within the other, with the primary or load-lifting pistonV operating in the inner piston; and one object of the invention is to provide for elevating the inner cylinder at the same time the load-lifting piston is being raised.

A further object is to provide an effective cushion for the load-lifting piston operative at the beginning and completion of the strokes, whereby jolts incident to starting and stopping are avoided.

A further object is to so construct the hoist as to provide for perfect and absolute control of the load at all stages of the lifting and lowering operations, lthus precluding possibility of a premature drop.

A further object is to provide improved valve mechanism, also to provide for constant lubrication of the Working parts.

In the accompanying drawings, Figure 1 is a vertical sectional View of a hoist embodying myinvention, the same being distended ready for hoisting. Fig. 2 is a similar View, all portions of the hoist being in raised or elevated position. Fig. 3 is a detail sectional View of the valve.

Referring to the drawings, 2 indicates the outer cylinder threaded at the exterior of its extremities to receive rings 3 and 4, respectively forming flanges against which bear the peripheral extremities of top and bottom cylinder-heads 5 and 6, respectively, with clamping-rods 7 passing through the heads Serial No. 117,800. (No model.)

is closed by threaded head 11, and this head is formed with a port closed by plug 12 for the purpose presently to be stated. Bottom head '13 of cylindel` 8 is preferablyanged peripherally to overlap ring 14, threaded on the cylinder extremity, to Which it is united by bolts 15.

16 is the piston operative in ,cylinder 8,l 17 the rod depending therefrom through stuffing-box 9 in head 13, and 18 the load-sustaining hook at the extremity of the rod.

Below the plane of piston 10 cylinder 8 is formed with a suitable numberof ports 19, each of which is preferably narrow vertically and elongated horizontally, with an inverted- V-shaped extension 20 on the upper side,reach ing to the bottom plane of piston 10. By means of these ports the cylinder 8 and space 2 between the cylinders are in constant communication. These communicating spaces, each having a mobile end wall-t0 wit, the pistons-combine to form a space which is lled with oil or other exiblejinelastic iiuid, whereby the area of the fluid-space is constant. The parts are so proportioned that with cylinder 8 raised space 2 is of nearly the same area as the space Within said cylinder, with piston 16 in lowermost position, the cylinder havingslightly-greaterarea for accommodating a small body of oil, which serves to cushion the stroke at its uppermost limit, as will be presently explained. The oil-space may be filled through the valved Ifunnel-inlet 21, near the upper end of cylinder 2. It Will be observed that all the Working parts and surfaces are thoroughly and constantly lubricated by the body of oil contained within the hoist.

For the admission of air tothe under side of piston 16 cylinder-head 13 is formed with port 22, which communicates with the center of valve-case 23, secured to the under side of the head. A spool-shaped valve 24 is mov- IOO able longitudinally in the case, being provided with stems 25, which project through the case ends, where they are engaged by the oppositely-positioned angular latches 26, and depending from these latches are operatingchains 27, preferably connected at their lower ends to form a balance. Normally the valve is held centered by springs 28, confined on stems 25, with one head of the valve covering inlet-port 29 and the other head covering exhaust-port 30. Obviously movement of the valve in one direction will place ports 22 and 29 in communication, admitting air to the cylinder, while an opposite movement opens the exhaust.

In operation when the mechanism is lowered for hoisting, as in Fig. 1, piston 10 rests on cylinder-head 6, with all the oil con tained in cylinder S and with ports 19 covered by head 6, save the points of port enlargements 20, which are in the plane of the meeting faces of piston 10 and head 6. Air being admitted tothe under side of piston 16, upward pressure of the latter starts the oil through the ports and between said meeting faces, and the start may be facilitated by beveling head 6 at 6. The start is gradual, however, owing to port contractions 20, through which the oil iirst emerges; but as piston 10 rises, and with it cylinder 8, the full areas of the ports are uncovered and the hoist attains its maximum speed, the oil flowing from cylinder 8 into space 2 and operating to lift piston 10 simultaneously with the upward movement of piston 16 in cylinder 8. The speed under given air-pressure and load is determined by the number and area of ports 19, as will be understood. Approaching the uppermost limit of its movement piston 16 gradually moves over and closes ports 19 and cushions against a small body of oil 3l, confined between the same and cylinder-head 11, thereby arresting the motion easily and without jar. At the beginning of the downward stroke oil is admitted in gradually-increasing amount as they are uncovered by lowering of piston 16, affording an easy start, and at the completion of said stroke gradual covering of said ports by cylinder-head 6 checks and cushions the stop. At all stagesof the lift the load is positively supported by the air under pressure and oil or other fluid and whether raisingor lowering is under complete control of the operator, with means acting automatically to effect a gradual stop devoid of jolts at either limit of movement. Two independentyetabsolutely-balanced movements are accomplished simultaneously-viz., the raising of piston 16 in cylinder 8 and. the upward movement of the latter bodily within cylinder 2. Thus piston 16, in effect, comprises a primary load-lifting device, cylinder 8 a movable carrier in which the piston moves, and cylinder 2 a support in which the carrier moves, with the movements of the load-lifting device and carrier accomplished simultaneously and at like speeds.

With the mechanism here shown and described a hoist is provided having doublestroke capacity, which when contracted occupies no more head-room than a single-stroke hoist.

The mechanism may be converted into a single-stroke hoist by removing plug 12, so that when piston 16 rises the oil is exhausted intocylinder 2, with cylinder 8 inactive.

While I have here shown and described the preferred embodiment of my invention, I do not confine myself thereto, as within the scope of the appended claims the hoist may be varied in many particulars and structural details without departing from the spirit of the invention.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. Improved hoisting mechanism comprising two cylinders-one movable within the other, a load-carrying piston operative in the inner cylinder, a duid-inlet connected to and movable with the inner cylinder for admitting fluid under pressure which actuates said load-lifting piston, and means actuated by the movement of the load-lifting piston for simultaneously moving the inner cylinder in the outer cylinder.

2. Improved hoisting mechanism comprising two communicating cylindei's--one movable within the other, a load-lifting piston operative in the inner cylinder, a piston rigid with the inner cylinder fitting the outer cylinder, a body of liquid common to both cylinders and filling the space between the two pistons, and a duid-inlet connected to and movable with the inner cylinder for admitting fluid under pressure which actuates said load-lifting piston.

3. Improved hoisting mechanism comprising an outer cylinder adapted to be sustained in upright position, an inner cylinder movable vertically as a piston through the bottom head of the outer cylinder, a piston-head on the inner upper end of the inner cylinder fitting the outer cylinder, a piston movable vertically in the inner cylinder, a load-sustaining rod depending from said last-named piston and movable vertically through the bottom head of the inner cylinder, the inner cylinder being open to the outer cylinder beneath the plane of the piston-head working in the outer cylinder, a body of liquid common to both cylinders and lling the space therein between said piston-heads, and a fluid-inlet connected to and movable with the inner cylinder for admitting duid under pressure to the under side of the piston-head working in the inner cylinder.

l. Improved hoistingapparatus comprising a cylinder provided with ports, a load-lifting piston operative therein, a body of liquid within the cylinder and adapted to be discharged through said ports by the advance of the piston and means constructed and ar- IOO IIO

ranged to retard the iiow of said liquid as the piston approaches the inward limit of its movement thereby cushioning the piston.

i 5. Improved hoisting mechanism comprising two communicating cylinders-one movable within the other, a piston rigid with the inner cylinder iitting the outer cylinder, a load-carrying piston operative in the inner cylinder, and means constructed and arranged to retard the flow of liquid from one cylinder to the other as the inner cylinder either approaches or reeedes from its positions of eX- treme adjustment.

6. Improved hoisting mechanism comprising two communicating cylindersone movable within the other, a piston rigid with the innercylindertitting the outercylinder,aload carrying piston operative in the inner cylinder, and means constructed and arranged to retard the flow of liquid from one cylinder to the other as the inner cylinder approaches its downward limit of travel.

7. Improved hoisting mechanism comprising two communicating cylinders-one movable within the other, a piston rigid with the innercylinderittingthe outercylinder,aload carrying piston operative in the inner cylinder, and means constructed and arranged to retard the i'low of liquid from one cylinder to the other as the piston within the inner cylder approaches its upward limit of travel.

8. Improvedhoistingapparatuscomprising a cylinder provided with side ports adjacent one end, said ports being of irregular outline with their parts of smallest capacity nearest said cylinder end, a load-lifting piston operative in the cylinder and adapted to cover or partially cover said ports, and a body of liquid within the cylinder and adapted to be discharged through said ports by the advance of the piston, the piston approaching and first covering the larger portions of the ports, thereby diminishing the discharge of liquid therethrough and cushioning the stroke ofthe piston.

9. Improved hoisting mechanism comprising an outer cylinder, an inner cylinder movable through a head of the outer cylinder, a

' piston-head on the inner cylinder iitting the outer cylinder and adapted to rest on the outer-cylinder head when the inner cylinder is distended, the inner cylinder being formed with side ports having contracted upward extensions extending to the bottom plane of said piston for the purpose described, a loadcarrying piston operative inl the inner cylinder, and a body of liquid common to both der, and a body of liquid common to both.

cylinders through said ports and illing the space between said pistons.

11. Improved hoisting mechanism comprising an outer cylinder, an inner cylinder movable through a head of the outer cylinder, a v

piston on the inner cylinder iitting the outer cylinder, the inner cylinder having side ports placing in communication the inner cylinder and the space between the cylinders, a valved port in the inner end of the inner cylinder, a piston operative inthe inner cylinder, and a body of liquid common to both cylinders through said side ports and filling the space between the pistons.

12. Improved hoisting mechanism comprising a cylinder, a load-carrying piston operative therein, a valve-case having a central j port communicating with the cylinder and also formed with inlet and exhaust ports at either side of said cylinder-port, a spoolshaped valve, springs acting vto normally hold the valve with the inlet and exhaust ports covered by the valve-heads, and valve-actuating means.

13. Improved hoisting mechanism comprising a cylinder, a load-carrying piston operative therein, a valve-case having a central port communicating with the cylinder and also formed with inlet and exhaust ports at either side of central port, a spool-shapedv valve, springs acting to hold the valve with the inlet and exhaust ports closed, stems projecting from the valve ends through opposite ends of the case, and actuating-latches operatively engaging the projecting ends of the stems.

ICO

In testimony whereof I ax my signature in presence of two witnesses.

FREDERICK C. WEBER. Witnesses:

J. M. NEsBrr, ALEX. S. MABoN. 

